Accurate duplication of the genome requires the regulated initiation of replication at specific origins of replication, sites at which the pre-replicative complex (pre-RC) assembles. Specific sequences associated with metazoan origins of replication have not been identified and the mechanism by which origins of replication are selected remains unclear. To learn more about origin specification in metazoans, I will use biochemical techniques to identify proteins that associate with the pre-RC in Drosophila melanogaster. To characterize the roles of these proteins, I will deplete them using RNAi and measure the effects on replication initiation in general and on pre-RC assembly at numerous origins across one arm of the [unreadable] Drosophila genome. [unreadable] [unreadable]